Multiple Pregnancy

Everybody is, or should be, interested in twins.H. H. NewmanTWINNING occurs often enough — approximately 1:80 pregnancies — to constitute an important biologic event. Because of the frequency with which obstetric and neonatal hazards accompany multiple pregnancy, it is recognized as having considerable medical importance. Although it has long been known that two classes of twins exist, so-called identical and fraternal twins, it was not until Sir Francis Galton, the cousin of Charles Darwin, proposed twins as model for the understanding of disease that twin research became an active field.1 Galton suggested that by comparison of various findings . . .